1. Field of the Invention
The present invention relates to a connection structure for connecting electrically and mechanically electronic components or devices such as a printed circuit board, an LSI, an IC, a display device, a switch, a printer unit or a battery.
2. Description of the Prior Art.
In an electronic apparatus such as a calculator, a hand-held computer, a hand-held word-processor, a pocket radio, a tape recorder or a video camera containing electronic components such as the above-mentioned, electronic components or devices such as a printed circuit board or an LSI are mounted inside the apparatus, and these electronic components or devices are mutually connected electrically by a lead wire or printed wiring, and furthermore are connected mechanically by a mechanically connecting member such as a screw, a rubber pressing member or adhesive.
FIGS. 1A and 1B show a calculator as an example of such an apparatus. This calculator comprises an upper case 1 and a lower case 4, each case being formed into a flat rectangular body shape.
The upper case 1 and the lower case 4 are secured in one piece by screws or adhesive.
A facing plate 2, formed by a thin sheet of aluminum or similar material, on a surface of which a special design is worked by means of offset printing, etching or the like, is adhered to a surface of the upper case 1 by adhesive or similar agent.
A keyboard 3 having a plurality of keys is disposed on the surface of the upper case 1.
A flat package type LSI 5 is disposed on a printed circuit board (not shown) inside the case. A (+) side terminal 5a and a (-) side terminal 5b are disposed separately on a right and a left side of this LSI 5.
Reference numerals 6a and 6b denote batteries which are connected in series, for example, through an intermediate contact plate (not shown). A (+) electrode and a (-) electrode of the batteries 6a and 6b are connected to a power supply pattern on a printed circuit board through electrically conductive sheet springs 7 and 8, respectively.
Reference numeral 9 denotes a liquid crystal display device for displaying an input, a result of a calculation, or some other required information.
In calculators of the type just described, the known arrangement of electrical connections among the components or devices in the electronic apparatus having the structure described above suffers from the problems described below.
(1) A connection between the liquid crystal display device 9 and the printed circuit board is made by a conductive rubber connector in which conductive rubber and insulating rubber are stacked in layers at equivalent pitch or by a heat seal member. This connecting means, however, has the defects of being expensive and of involving a large number of steps during assembly.
(2) The (+) and (-) electrodes of the batteries 6a and 6b are connected to a predetermined pattern on the printed circuit board via the individual sheet springs 7 and 8, so that when the printed circuit board is a single-sided board and the (+) and (-) input terminals of the LSI 5 are positioned on opposite sides, i.e., on the right and left sides as shown in FIG. 1A, the (+) power supply terminal of the LSI 5 and the (+) battery terminal must be connected with a jumper wire. This causes an increase in cost.
(3) When two printed circuit boards are arranged in layers via an insulating sheet, the top and bottom printed circuit boards must be connected electrically at a plurality of positions. In conventional arrangements, rubber piece members are provided at predetermined connecting positions and the elastic force of the rubber produced when the cases 1 and 4 are pressed together presses the upper and lower printed circuit boards against each other, so that these printed circuit boards are connected electrically.
When an arrangement such as this structure is adopted, however, the elastic force of the rubber is large, so that when a number of rubber piece members are disposed at a number of pressing positions, the pressure of the rubber opens out the upper case 1 and the lower case 4. Consequently, a large number of screws for securing the upper and lower cases must be used, and as a result, the number of parts and the number of assembly steps increase, which cause an increase in costs.